libgtk2-unique-perl software package provides module for single instance applications, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libgtk2-unique-perl
libgtk2-unique-perl is installed in your system.
Make ensure the libgtk2-unique-perl package were installed using the commands given below,
$ sudo dpkg-query -l | grep libgtk2-unique-perl *
You will get with libgtk2-unique-perl package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Perl |
| Package | libgtk2-unique-perl |
| Version | 0.05-2+b3 [s390x], 0.05-2+b1 [ |
| Description | module for single instance applications |
| Sub Section | Perl |